Friday, October 05, 2012

New Study Provides More Evidence that Vaping is Much Safer than Smoking and Finds Few Hazardous Chemicals in "Secondhand" Vapor

A new study published in this month's issue of the journal Inhalation Toxicology provides more evidence - from laboratory analysis of the constituents in "secondhand" vapor from electronic cigarettes - that vaping is much safer than smoking and that "secondhand" vapor is much less hazardous than secondhand smoke.

(see: McAuley TR, Hopke PK, Zhao J, Babaian S. Comparison of the effects of e-cigarette vapor and cigarette smoke on indoor air quality. Inhalation Toxicology 2012; 24(12): 850-857.)

According to the study: "Four different high nicotine e-liquids were vaporized in two sets of experiments by generic 2-piece e-cigarettes to collect emissions and assess indoor air concentrations of common tobacco smoke by products. Tobacco cigarette smoke tests were conducted for comparison. Comparisons of pollutant concentrations were made between e-cigarette vapor and tobacco smoke samples. Pollutants included VOCs, carbonyls, PAHs, nicotine, TSNAs, and glycols."

The chief results of the study were that:

1) Very few of the chemicals present in secondhand smoke were detected in the electronic cigarette vapor.

2) Of the few chemicals that were detected, the levels were substantially lower than those present in secondhand smoke.

The only compound of significant concern was formaldehyde, but its levels were much lower in the electronic cigarette vapor than in the tobacco smoke. One hypothesis is that formaldehyde may result from the heating of propylene glycol. While this is enough concern to warrant efforts to try to find ways to reduce the formation of formaldehyde in the vaporization process, this finding is consistent with previous research which also detected low levels of formaldehyde and does not alter the basic conclusion that these products are much safer than cigarettes.

In a press release accompanying the study, I am quoted as stating: "This study demonstrates that the risks of secondhand vapor from electronic cigarette use are very small in comparison to those associated with secondhand tobacco smoke. While secondhand smoke must be eliminated in workplaces and public places, the current data provide no justification for eliminating electronic cigarette use in these places."

Bill Godshall of Smokefree Pennsylvania is quoted as stating: "For more than 25 years Smokefree Pennsylvania has been advocating indoor smoking bans. Based on the results of this study I see no reason for e-cigarettes to be included in smoking bans."

Dr. Murray Laugesen of Health New Zealand is quoted as stating: "The results of this study confirm the findings of my last 4 years of research. E-cigarettes pose no discernible risk to public health."

The Rest of the Story

While I wouldn't go as far as Dr. Laugesen to say that this study confirms that there is "no discernible risk" to public health from electronic cigarettes, I do believe that the results confirm the previous evidence demonstrating that vaping is much safer than smoking and that there are few concerns related to the safety of secondhand vapor from electronic cigarettes.

It is important to keep in mind that the electronic cigarette vapor in this study was produced by machines, not by humans. Thus, none of the constituents of the vapor were absorbed in the lungs as they would be normally. So the study is going to overestimate the actual levels of these constituents that would be produced by actual vaping.

There are three reasons that I would not say electronic cigarettes pose no risks. First, they contain nicotine, which has adverse cardiovascular effects. So we are not expecting that electronic cigarettes will ever be viewed as being absolutely safe. Second, there are some acute respiratory irritant effects of propylene glycol inhalation. The implications of these effects for chronic use are not yet understood, but more research needs to be done before we know whether there might be some long-term respiratory effects. Third, there are low levels of a few specific volatile organic compounds. Of most concern is formaldehyde.

Nevertheless, given the thousands of chemicals in tobacco smoke, there is no doubt that vaping is much safer than smoking and that secondhand vapor is far less hazardous than secondhand smoke.

Before efforts to ban vaping in public places are justified, there need to be studies that document levels of actual human exposure to the vapor constituents in real-life settings using measurements in ambient air under realistic conditions. This laboratory study is useful in helping to define the maximum possible exposure levels, but real-life exposure is likely much lower. Before we can state that there is any risk of secondhand vapor to nonsmokers, we need to actually measure the exposure under realistic conditions.

Hence, my position is that there is currently no evidence to warrant banning vaping in public places.

The bottom line is that while further research is needed to precisely characterize any long-term risks that may be associated with vaping, the current evidence is sufficient to conclude that vaping is much safer than cigarette smoking. Health advocates should encourage, rather than dissuade, the use of electronic cigarettes as a smoking cessation or smoking reduction tool among current smokers, especially those who have failed to quit using traditional smoking cessation drugs.

No comments: